From 8b05309eb83cd96576b4fd65e809d1cf22c61f10 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Luca=20G=C3=BCttinger?=
 <38906805+Luca-Guettinger@users.noreply.github.com>
Date: Sat, 30 May 2026 01:52:02 +0200
Subject: [PATCH] Fix NPE from map corruption when sync handlers register
 entries during init

---
 .../modularui/value/sync/PanelSyncManager.java            | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncManager.java b/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncManager.java
index c05ac874d..a5933373f 100644
--- a/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncManager.java
+++ b/src/main/java/com/cleanroommc/modularui/value/sync/PanelSyncManager.java
@@ -60,7 +60,13 @@ public PanelSyncManager(ModularSyncManager msm, boolean main) {
     @ApiStatus.Internal
     public void initialize(String panelName) {
         this.panelName = panelName;
-        this.syncHandlers.forEach((mapKey, syncHandler) -> syncHandler.init(mapKey, this));
+        var snapshotKeys = new ArrayList<>(this.syncHandlers.keySet());
+        for (var mapKey : snapshotKeys) {
+            var syncHandler = this.syncHandlers.get(mapKey);
+            if (syncHandler != null) {
+                syncHandler.init(mapKey, this);
+            }
+        }
         this.locked = true;
         this.init = true;
         this.subPanels.forEach((s, syncHandler) -> this.modularSyncManager.getMainPSM().registerPanelSyncHandler(s, syncHandler));